So I forgot to add in some lactose syrup until after I sprinkled the yeast on top of finished wort. Not thinking, I stirred it in. Will the yeast still start to ferment in a non-aerated wort without floating on the top?

How long ago did you pitch? If it was a matter of minutes you could still do some vigorous aerating of the wort, which would help. As far as I know, stirring in the yeast might deplete your yeast numbers slightly but shouldn't be too damaging.

I always stir my yeast in and aerate after pitching and have turned out decent beer every time.

I forgot to areate 2 batches ago. On the 3rd day, i finally realized it because fermentation had not started. I sanitized the handle of my brewing spoon and stirred the crap out of it until my arm was on fire. Ferm kicked off within 8 hrs.

Always aerate with all yeast. They need o2 for the reproductive phase before visible fermentation starts. Boiling the wort drives off o2,which needs to be replaced. Even the act of pouring the chilled wort & top off water into the FV will add some o2 back in.

Well the thing is dry yeast comes with suficient lipids to double their size without oxygen, doesn´t hurt to aerate actually it helps you but is not critical with dry yeast, your laga time can be a little more but it will be fine.

Well the thing is dry yeast comes with suficient lipids to double their size without oxygen, doesn´t hurt to aerate actually it helps you but is not critical with dry yeast, your lag time can be a little more but it will be fine.

Well awesome. I just got home from a grueling 16 hours of First Lego League championship with my son. Came in to a perfectly fermenting batch of Zombie Dust, with modifications. Little tidbits of knowledge like this certainly come in handy. Thanks for all the responses!